If you think people are shitty, that means you are comparing them to some standard of non-shittiness, and they didn't live up to that standard. What makes you think this standard is any more "real" than what you perceive around you? Did you come up with it yourself, or is it something that was taught to you by society?

The only reason we're not tapping into this selfish and destructive behaviour is because of fake constructs placed on us by society.

It's not fake in the sense that social behavior isn't fake. It's a human trait that has served us well as a whole, just like aggression and cunning. The concept of selfishness being bad only exists because there is a social instinct to enforce morals. It is otherwise a neutral thing, just like any other aspect of nature. Same goes for love and affection, ultimately these exist only because they have been helpful at creating social bonds and make survival easier. So if everyone experienced genuine love it would still be "fake" based on your idea of what fakeness is.